Battery booster circuit containing voltage sensing means

ABSTRACT

A battery booster circuit for use in conjunction with an emergence or road service vehicle for aiding stalled or disabled vehicles in which a first and a second battery carried by said road service vehicle are so connected that both batteries will be charging or discharging at any given time at substantially the same rate and in which current amplifying means are employed in a voltage sensing circuit to determine that correct polarity connections exist between the batteries of the service vehicle and between the booster charger system and the battery of the stalled or disabled vehicle, said voltage sensing means being operative even where the battery of the stalled or disable vehicle has no appreciable voltage.

United States Patent 15] 3,654,538 Gardberg Apr. 4, 1972 [541 BATTERYBOOSTER CIRCUIT 3,341,762 9/1967 Rockofi' ..320/2s x CONTAINING VOLTAGESENSING 3,343,057 9/1967 Smith ...320/25 X MEANS 3,456,181 7/1969Godshalk... ..320/25 3,105,910 10/1963 Chambers ..320/2 [72] Inventor:Joseph Gardberg, 585 W. 51st Street, Hi-- 1 aleah, Fla. 33016 PrimaryExaminer-William M. Shoop, Jr. Atlorne Johnston, Root, OKeeffe, Keil,Thom son & Shur- 22 Filed: Jan. 19, 1970 eff y p [211 App]. No.: 3,866

[57] ABSTRACT [52] U.S. Ci ..320/7, 320/15, 320/25, A battery boostercircuit for use in conjunction with an emer- 320/93 gence or roadservice vehicle for aiding stalled or disabled 51 Int. Cl. .Q1i02 7/00vehicles in which first and a Second battery carried by said 58 Field ofSearch ..320/7, 15, 22, 25, 26,48; road Service vehicle are Connectedthat bah batteries will 307/138 be charging or discharging at any giventime at substantially the same rate and in which current amplifyingmeans are em- [56] References Cited ployed in a voltage sensing circuitto determine that correct polarity connections exist between thebatteries of the service UNITED STATES PATENTS vehicle and between thebooster charger system and the battery of the stalled or disabledvehicle, said voltage sensing 3,129,372 4/1964 watt en ..320/1 5 meansbeing operative even where the battery f the Stalled or 3,217,225 1H1965 Gottlieb et a1. .....320/25 X disable vehicle has no appreciablevohage' 3,258,672 6/1966 Godshalk et a1... ..320/25 3,281,816 10/ 1966Raymond ..320/ UX 6 Claims, 4 Drawing Figures 43b RED fdfiLE TOPDS/f/VETERM/N44 /40b -27 6 t IUX/L/JR) 923/26 547754) J WHITE r0 427%,

258 A// 1014/ ML 46 1 125221: 32 I 52:Z 35 ca a 1 356 R L J 4% Jim 5 26a45 37 i 1 -42; 266/ /mmW/05 E I /7 *mwmz a;

29 e 1 la 0/! 25b 39a 5 name 501:71'0/0 .1 E 29 9 47 Bu [K 64516 H z, 14. 215 951 Patented April 4, 1972 2 Sheets-Sheet 2 are destructive tothe booster BATTERY BOOSTER CIRCUIT CONTAINING VOLTAGE SENSING MEANSBACKGROUND OF THE INVENTION This invention relates to apparatus forenergizing the battery of a stalled or disabled vehicle and to batterybooster apparatus having internal means for detecting improper polarityconditions existing on the boosters output cables.

Previous battery boosters have been designed which can be connectedacross a disabled vehicles discharged battery for the purpose ofstarting the disabled vehicle or recharging the battery. It is possible,however, to connect the boosters output cables to the wrong polarityterminals on the discharged battery. When this occurs high electricalcurrents flow which circuitry, as well as the battery being charged.

In the low mode of operation of the typical two battery starter, onlythe vehicle battery furnishes current for starting the battery of adisabled vehicle. If the jump is a difficult one the vehicle battery isrun down while the auxiliary battery of the emergency vehicle remainsfully charged. When the jump period is over, there is a high currentflow between the vehicle battery and the booster battery. This is alsotrue for the starting of the emergency vehicle itself.

It is an object of the present invention to provide an improved batterybooster circuit which can detect improper polarity conditions on itsoutput terminals under low voltage conditions which will not activateprevious systems.

It is a further object of the present invention to provide an improvedbattery boosting apparatus which can connect an emergency vehiclesbattery in series with an auxiliary battery for the purpose ofdelivering a high voltage charging and starting capability, which alsoprovides a convenient means for switching back to low voltage to preventdamage to disabled vehicle battery.

Still another object of the present invention is to provide an improvedbattery boosting apparatus designed to connect an emergency vehiclesbattery in parallel with an auxiliary battery so that the two batteriesmay be charged simultaneously from the emergency vehicle s chargingsystem.

Yet another object is to provide circuit means for insuring that bothbatteries of a service vehicle will be charging or discharging at anygiven time at substantially the same rate.

Other objects will become apparent to those skilled in the art from thefollowing description of the invention.

SUMMARY OF THE INVENTION The battery booster circuit disclosed herein isdesigned to be installed in an emergency vehicle to aid in startingdisabled vehicles. Jumper cables are connected between the output of thebattery booster and the battery in the disabled vehicle. In on eembodiment of the invention, a current amplifying voltage sensingcircuit is arranged to detect whether the jumper cables have beenconnected to the proper polarity terminals on the battery in thedisabled vehicle even where the battery of the disabled vehicle has noappreciable voltage. A transistor circuit conveniently can be use forthis purpose. In one such embodiment the transistor is arranged in thegrounded emitter configuration wherein the transistors emitter isconnected to the emergency vehicles ground. Both the battery boostersnegative output terminal and the negative terminal of the emergencyvehicle's battery are also connected to ground in' the emergencyvehicle. A positive 12 volts is supplied through the emergency vehicle'signition switch and a series connected diode and resistor to the basecircuit of the transistor, hereinafter called the polarityv checkingtransistor. The positive output terminal of the battery booster isconnected into the base circuit of the polarity checking transistor bymeans of a diode. When the battery boosters output cables are connectedto the proper terminals on the battery in the disabled vehicle, thepolarity checking transistor will be in full conduction or saturated.When the battery boosters output cables are connected improperly to thebattery terminals in the disabled vehicle, the voltage in the basecircuit of the polarity checking transistor will be insufficient toallow the transistor to conduct and the transistor will be cutoff.

An auxiliary battery is also utilized in connection with the batterybooster. It is important that the auxiliary battery be properlyinstalled to prevent the flow of destructive electrical currents. Whenproperly installed the negative terminal of the auxiliary battery isreferenced to emergency vehicle ground through a resistor. The positiveterminal of the auxiliary battery is connected to the base circuit ofthe polarity checking transistor through a diode. When the auxiliarybattery is properly installed the polarity checking transistor willconduct. When the auxiliary battery is improperly installed, the voltagein the base circuit of the polarity checking transistor will beinsufficient to cause the transistor to conduct and the transistor willbe cutoff.

Four distinct modes of operation characterize a preferred embodiment ofthe subject invention. These are:

a. the high voltage starting mode;

b. the low voltage starting mode;

c. the charging mode; and

d. the emergency vehicle starting mode.

In the high voltage starting mode, the emergency vehicles battery andthe auxiliary battery are connected in series using relay means.Specifically, when the battery boosters output cables are properlyconnected to a battery in a disabled vehicle, the polarity checkingtransistor conducts. A start switch and an activate relay are connectedin series with the transistor's collector circuit. When the transistorconducts and the start switch is closed, the start relay will beenergized. A mode switch is employed which permits selection of the highor low voltage mode of operation. With the mode switch in the highvoltage position, the energizing of the activate relay, in turn,activates other relays which connect the negative terminal on theauxiliary battery to the positive terminal on the emergency vehiclesbattery and the positive terminal on the auxiliary battery to thepositive output terminal of the battery booster circuit. The highvoltage mode is required in those instances where the disabled vehicleis particularly difficult to start.

In the second mode of operation, the low voltage mode, the

mode switch is set to the low voltage position. When the activate relayis energized, as described in connection with the high voltage mode ofoperation, additional relays are activated which connect the emergencyvehicles battery in parallel with the auxiliary battery and also connectthe parallel combination of the two batteries to the battery boostersoutput terminals. The low voltage mode of operation is selected whenprolonged cranking of the disabled vehicles engine is necessary.

In the third mode of operation, the charging mode, it is desirable toconnect the emergency vehicle 's battery in parallel with the auxiliarybattery in order to obtain an equal charge on each battery.Specifically, when no improper polarity conditions appear on the batterybooster output terminals and the auxiliary battery is properlyinstalled, the polarity checking transistor will conduct. A charge relayis connected to the collector circuit of the polarity checkingtransistor in series with a normally closed contact on the activaterelay. With the polarity sensing transistor conducting and the activaterelay not energized, the charge relay will be energized. When thecontacts on the charge relay close, a second relay is activated whichconnects the emergency vehicles battery in parallel with the auxiliarybattery. In this way both batteries can be charged from the emergencyvehicles charging system.

In the fourth mode of operation, the emergency vehicles starting mode,the emergency vehicles battery and the auxiliary battery are connectedin parallel while the emergency vehicle is being started. For thispurpose, a relay, called an emergency vehicle start relay, is connectedin series with a normally closed contact on the activate relay betweenthe collector circuit of the polarity checking transistor and thestarter solenoid in the emergency vehicle. When the emergency vehicle isbeing started and the polarity checking transistor is conducting, theemergency vehicle start relay will be activated. This will, in turn,activate other relays to connect the emergency vehicle's battery inparallel with the auxiliary battery. The parallel battery combination isthen available to supply starting current to the emergency vehicle.

Further features and advantages of the invention will become morereadily apparent from the following description of a specificembodimentof the invention when taken in conjunction with the accompanyingdrawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an electrical circuitdiagram for a typical two battery starting circuit;

FIG. 2 is an electrical circuit diagram illustrating one approach toreducing the high transient current flows characteristic of the circuitdescribed in connection with FIG. 1;

FIG. 3 is an electrical circuit diagram of a polarity checking circuit;and

FIG. 4 is an electrical circuit diagram showing one preferred embodiment of the subject invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT FIG. 1 is a partial electricalcircuit diagram showing a typical two battery starting circuit 1,utilized for starting disabled vehicles which have discharged orpartially discharged batteries. Starting circuit 1 is generallyinstalled in an emergency vehicle which is used to provide road serviceto disabled vehicles. Battery 2, the emergency vehicle battery, andbattery 3, an auxiliary battery mounted in the emergency vehicle, areused to provide the electrical energy necessary to start a disabledvehicle with a discharged or partially discharged battery.

In the high voltage mode of operation, i.e., when a high startingvoltage is required, it is necessary to connect batteries 2 and 3 inseries. This is accomplished by closing switch 5. Closure of switch 4then connects the positive terminal of battery 3 to cable 6. Thus, wherebatteries 2 and 3 are 12 volts each, the voltage across jumper cables 6and 7 will be 24 volts. When jumper cables 6 and 7 are connected to adischarged 12 volt battery, the current flow is limited by the totalresistance of the circuit. Consequently, the size of the jumper cablesis selected to limit the current flow in the circuit to some desiredmaximum value. When batteries 2 and 3 are connected in series, the samecurrent flows in each battery and the rate of discharge is the same.

After the jumper cables are disconnected from the battery in thedisabled vehicle, switches 4 and are opened and switches 8 and 9 areclosed. Thus, batteries 2 and 3 are placed in parallel, andconsequently, both batteries may be recharged from the emergencyvehicles charging system not shown). This insures that both batteriesare always at the same state of charge.

In the low voltage mode of operation, wherein only a low startingvoltage is required, switch 10 is closed and switches 4, 5, 8, and 9remain open. Thus, only the emergency vehicles battery 2 is connected tojumper cables 6 and 7. If there is difficulty in starting the disabledvehicle, the emergency vehicle s battery 2 will become discharged, whilethe auxiliary battery 3 remains fully charged. When cables 6 and 7 areremoved from the battery in the disabled vehicle and switches 8 and 9are closed, high currents flow between the auxiliary battery 3 and theemergency vehicle battery 2. These high currents are not desirable sincethey would require high current contactors for the charging circuit withattending large holding currents increasing the load on the generator.

The circuit indicated in FIG. 2 eliminates the high currents describedin connection with FIG. 1 which flow between auxiliary battery 3 and theemergency vehicles battery 2 after starting a disabled vehicle in thelow voltage mode of operation. When it is desired to perform a lowvoltage starting operation, switches 4, 8 and 9 are closed. Thisparallels batteries 2 and 3. During the starting operation bothbatteries are discharged equally. Consequently, when the low voltagestarting operation is complete, both batteries being in parallel and atthe same level of discharge, high currents will not flow between them.

During the start of a disabled vehicle it is necessary to place jumpercables 6 and 7, described in connection with FIGS. I and 2, on thecorrect terminals of the battery in the disabled vehicle. If the jumpercables are placed on the wrong terminals, i.e., with the wrong polarity,the starting apparatus can be damaged. A partial circuit diagram of apolarity checking circuit is shown in FIG. 3.

With jumper cable 6 placed on the positive terminal of the battery (notshown) in the disabled vehicle and cable 7 placed on the negativeterminal of said battery, current will flow from the +12 volt DC source20 through resistor 11 and diode 12 into the base 13 of transistor 14.Under these circumstances, transistor 14 will become saturated and whenswitch 15 is closed, current will flow from the +12 volt DC source 20through relay coil 16a and switch 15 into collector 17 of transistor 14.Since transistor 14 is saturated, the current will pass throughtransistor 14 exiting at emitter 18 which is connected to ground. Whenrelay coil 16a is energized, relay 16 will operate causing contact 1612on relay 16 to close. The closure of contact 16b connects battery 19 tocable 6, thereby permitting current to flow from battery 19 throughcable 6 into the battery in the disabled vehicle. The return path forthe current flow from battery 19 is through cable 7 into the negativeterminal of battery 19.

If cables 6 and 7 are placed on terminals of the wrong polarity in thedisabled vehicle, the potential at the junction of diodes l2 and 27 andresistor 11 will be negative. Consequently, no current will flow intothe base 13 of transistor 14 and transistor 14 will remain in thenonconducting or cutoff condition. Thus, when switch 15 is closed, relaycoil 16a will not be energized since transistor 14 is in the cutoffstate and the necessary current to operate relay 16 cannot flow. Sincerelay 16 will not operate, contact 16b will not close and battery 19will not, therefore, be connected to cable 6. Thus, damage to battery 19will not occur as a result of being connected across a battery ofopposing polarity.

The circuit described in connection with FIG. 3 is incorporated in thepreferred embodiment of the battery booster circuit illustrated in FIG.4. In FIG. 4, when battery cables 6 and 7 are connected properly toterminals of the correct polarity on a battery in a disabled vehicle,base current for polarity checking transistor 14 will flow from lead-20,which is connected to the positive side of the emergency vehicle'sbattery 29 through the emergency vehicles ignition switch (not shown),through resistor 11 and diode 12 into base 13 of transistor 14, andthence through the emitter 18 into the negative bus 22, causingtransistor 14 to be in the saturated state. When transistor 14 issaturated, the voltage from collector 17 to emitter 18 will approach 0volts for the value of collector current required in this circuit. Thecathode side of diode 12 is connected as shown to base 13. Diode 21 isconnected between base 13 and negative bus 22, the cathode side of diode21 being connected to base 13. Negative bus 22 is connected to vehicleground. Diode 21 is utilized to provide proper biasing conditions fortransistor 14 and also to provide a path for the recovery current whichinstantly flows through diode 12 when a wrong polarity sensing is made.Thus, if switch 23a, a three position switch, is either in the III or L0position and either switch 15 or remote switch 260 are closed, currentwill flow from lead 20 through switch 23a, diode 24, relay coil 25a ofrelay 25, either switch 15 or remote switch 26a, into collector 17,thence through transistor 14 and out of emitter 18 into negative bus 22.Remote switch 260 is connected to the battery booster circuit by meansof plug 26b and jack 26a. The current flowing through relay coil 25awill energize relay 25.

If, on the other hand, c ables 6 and 7 are connected to terminals of thewrong polarity on the battery in the disabled vehicle, diode 27 willconduct and the base current necessary v to saturate transistor 14 willbe diverted through diode 27.

Consequently, relay 25 will not operate when either switch 15 or remoteswitch 260 are closed.

When properly installed, the negative terminal of auxiliary battery 28is connected through a 150 ohm resistor 31 to negative bus 22. Clearly,the wrong polarity installation of auxiliary batter 28 would bedistinctive in any paralleling of auxiliary battery 28 and emergencyvehicle battery 29. If the auxiliary battery 28 is installed such thatits polarity is reversed, the base current necessary to saturatetransistor 14 will be diverted through diode 30 into the reversedauxiliary battery 28. Again, relay 25 will not operate when auxiliarybattery 28 is reversed, since transistor 14 will be nonconducting orcutoff. The anode sides of diodes 27 and 30 are connected as shown tothe junction of resistor 11 and diode 12. From the foregoingdescription, it should be clear that relay 25 can only be operated whenauxiliary battery 28 is properly installed and cables 6 and 7 are notconnected to battery terminals of improper polarity. Correct polaritylamp 32 and series resistor 33 are connected in parallel with relay coil25a and switch 15 to provide an indication that the correct polarityconditions exist. When correct polarity exists, current flows from lead20, through switch 23a, diode 24, lamp 32, resistor 33 and saturatedtransistor 14, into the negative bus 22. In the circuitry described,lamp 32 will light only when transistor 14 is saturated.

Four distinct modes of operation are possible with the battery boostercircuit. In the charging mode it is necessary to connect batteries 28and 29 in parallel. When the emergency vehicle s ignition switch isturned on, a positive 12 volt DC will appear on lead 20. When theauxiliary battery 28 has been properly installed and cables 6 and 7 arenot connected to terminals of the wrong polarity, current will flowthrough diode 34, relay coil 35a and, if switch 15 or remote switch 260are not closed, through the normally closed contact 25b of relay 25 intocollector 17, thence through transistor 14, out of emitter 18 intonegative bus 22. Under these conditions, relay 35 will operate causingcontacts 35b and 35c on relay 35 to close. This places battery 28 inparallel with battery 29 insuring that the charging voltage appearingacross leads 36 will likewise appear across batteries 28 and 29. In thismanner both batteries will maintain the same state of charge.

In the emergency vehicle starting mode it is necessary to parallelbatteries 28 and 29 while the emergency vehicle is being started, sothat both batteries contribute to the starting of the emergency vehicle,and also, so that both batteries will be equally discharged. Again, ifthe auxiliary battery 28 is properly installed and cables 6 and 7 arenot connected to terminals of the wrong polarity, transistor 14 will bein the saturated state. While the emergency vehicle is being started,current will flow out of lead 37, which is connected to the S terminalof the emergency vehicles starter solenoid, through diode 38, relay coil39a, and, if switch 15 or remote switch 26c are not closed, through thenormally closed contacts 25b of relay 25 into collector l7, thencethrough saturated transistor 14, and out of emitter 18 into negative bus22. Since a positive 12 volts may not be present on lead if said lead 20is connected to the accessories terminal instead of the ignition switchduring starting of the emergency vehicle, but is present on lead 37,base current necessary to saturate transistor 14 is supplied throughresistor 44. Resistor 44 is connected between the anode side of diode 12and the cathode side of diode 38. The current passing through relay coil39a will cause relay 39 to operate closing contact 39b on relay 39. Theclosure of contact 39b allows current to pass through relay coil 40a.Relay 40 will then operate closing contacts 40b and 40c on relay 40.Closure of contact 400 allows current to pass through relay coil 41a,thereby operating relay 41 and closing contact 41b on relay 41. Theclosure of contact 40b connects the positive terminals of batteries 28and 29 together. Closure of contact 41b connects the negative terminalof battery 28 to negative bus 22. Thus, batteries 28 and 29 areconnected in parallel permitting both batteries to be used in startingthe emergency vehicle. The starting current will flow over leads 36.

In the third mode of operation, the high voltage starting mode, switches23a and 23b are set to the high position. If the auxiliary battery hasbeen properly installed and jumper cables 6 and 7 are connected to theproper battery terminals in the stranded vehicle, closure of eitherswitch 15 or remote switch 260, will energize relay 25 causing normallyclosed contact 25b on relay 25 to open and normally open contact 250 onrelay 25 to close. With switch 23b in the HI position and contact 250 onrelay 25 closed, current will flow through relay coil 42a therebycausing relay 52 to operate and contact 42b on relay 42 to close therebyconnecting the positive terminal of battery 29 to the negative terminalof battery 28. Thus, batteries 28 and 29 will be connected in series.Current will also flow through contact 250 on relay 25, normally closedcontact 3% of relay 39, and relay coil 430, into the negative bus 22.Current passing through relay coil 43a will energize relay 43 causingcontact 43b on relay 43 to close, thereby connecting the positiveterminal of battery 28 to jumper cable 6. Thus, for those situationsrequiring a high starting voltage, the series connected output voltagefrom batteries 28 and 29 is available across jumper cables 6 and 7.

In the fourth mode of operation, the low voltage starting mode, switches23a and 23b are set in the LO position. When switch 15 or remote switch260 is closed and transistor 14 is saturated, relay 25 will operateopening contact 25b on relay 25 and closing contact 250 on relay 25.Current will then flow through contact 25c, switch 23b, and relay coil40a into the negative bus 22. Relay 40 will operate causing contacts 40band 400 on relay 40 to close. When contact 40c closes, relay 41 willoperate closing contact 41b on relay 41. Batteries 28 and 29 will thusbe connected in parallel. Current will also flow through contact 250,normally closed'contact 39c, and relay coil 43a into negative bus 22.Relay 43 will operate closing contact 43b on relay 43, therebyconnecting the positive terminal on battery 28 to cable 6. By operatingthe batteries in parallel, both batteries discharge at the same rate.

A safety feature incorporated into the present invention is embodied innormally closed contact 39c on relay 39. During the period that theemergency vehicle is being started, relay 39 is operated causingcontacts 39c to open. Thus, relay 43 is prevented from operating whilethe emergency vehicle is being started, and no current will be suppliedto jumper cable 6 during this period. This is particularly importantsince the jumper cables may by lying loose in the emergency vehicle, andif they were energized while the emergency vehicle was being started,short circuit currents could flow.

Diodes 45, 46, 47, and 48 are utilized to reducetransients by providinga shunt path for coil currents when relays 25, 35, and 39 arede-energized.

While the foregoing description has referred to a specific embodiment ofthe invention, it will be apparent that many modifications andvariations may be made therein without departing from the spirit andscope of the invention.

I claim:

1. A battery booster circuit for use with a road service vehiclecomprising, in combination:

a. a first battery means having positive and negative terminals;

b. a second battery means having positive and negative terminals, thenegative terminal on said second battery means being connected toground;

c. first and second output cables, said first output cable beingconnected to ground;

. current amplifying voltage sensing means having inputs operativelyconnected to said second output cable and also to said first batterymeans, the output of said voltage sensing means being arranged toindicate whether said first battery means and said second output cablehaving been properly connected; and

e. control means operatively connected to the output of said voltagesensing means, said control means being arranged to connect said firstand second batteries in series and parallel combinations to said outputcables, said control means also being arranged to connect said first andsecond batteries in parallel to the road service vehicles between groundand the positive terminal on said second battery means, the pair ofcontacts on said third relay means being arranged to connect thenegative terminal on said first battery means to ground; and

starting and charging systems when said batteries are not e. a fourthrelay means having a coil and a pair of normally connected to saidoutput cables. open contacts, said coil and the pair of contacts on said2. A battery booster circuit in accordance with claim 1 first relaymeans being connected in series between wherein said voltage sensingmeans comprises: round and the positive terminal on said second battery,a. a current amplifying means connected to be driven by t e P ofcontacts lfif urth relay means being arcurrent from the road servicevehicle ignition switch or an 10 ranged toconnect the posrtrve terminalsatld first f accessory circuit operable with the engine of the roadsertery to Sard serfond output. whereby sard batrerles vice vehide; areconnected in parallel with said output cables. b. diode means connectedto the output cable such that im- A t y booster circuit in accordancewith claim 1 proper connection of the output cable to the emergencywherem sald control means rr g addrtronf vehicle will prevent theoperation of the amplifier and a first relay means havmg a cor] and a rof normally thus the means ofoperatiomand closed contacts, said firstrelay means being activated diode means connected 6 the first batterymeans such while said battery booster circuit is being used to service athat improper installation of said first battery will defer drsabledveh'cle; the drive current from the amplifier such as to prevent the aslecorrd relay means havmg a corrand first serfond paralleling of saidfirst and second battery means for of normally p ContactsZ d coil andthe Pall" of either charging or starting normally closed contacts onsaid first relay means being 3. A battery booster circuit in accordancewith claim 1 conrrected series r f thePurPut 9 vohrge wherein Saidcontrol m 6 ans includes in addition: sensing means and the ignitionswrtch in said road service anotmauy open Switch. vehicle, the firstpair of contacts on said second relay b. a first relay means having acoil and a pair of normally mean? bemg arranged r0 connect the neganvererrrrmal open contacts, said coil and said switch being connected onSard first r means to ground second Parr or in series between the outputof said voltage sensing means Contacts on Sald e ay m ans crng arrangedto and the ignition Switch in Said road Se Wice vehicle. connect theposrtrve terminals on said first and second n c. a second relay meanshaving a coil and a pair of normally barterres together f open contacts,said coil and the pair of normally open means for operarrvely 'j r Sardr contacts on said first relay means being connected in semeans to fchargrrg syrtem m Sard road, Servrce ties between ground and thepositive terminal on Said whereby sard batteries will be connected inparallel to the second battery means, the pair of normally open contactsToad F f h fg g y em when said battery on Said second relay means beingarranged to connect the booster circuit is not being used to service adisabled positive terminal of said second battery means to the Wherenegative terminal ofsaid first battery means. and 6. A battery boostercrrcurt in accordance with claim 1 I e a a n n d. a third relay meanshaving a coil and a pair of normally wherem Sard control meanslrlcludesflm addlnonj open contact, said coil and the pair of normallyopen cona first relay means g a 1011 and a part Of nol 'mally tacts onsaid first relay means being connected in series cursed crmtacts Sald ra merms bemg unrated between ground and the positive terminal on saidsecond 40 while said battery booster crrcurt rs being used to service abattery means, the pair of normally open contacts on said dlsabledvehrcle; third relay means being arranged to connect the positive a r rrelay mearrs 3 C011 a Parr or contacrs terminal of said first relaymeans to said second output Sard cor] and the r o normally P f saldcable, wherein said first relay means will operate when first relay "Fbeing q d n ser es between the said switch is closed, said first relaymean causing said Output orsard, P Serrsmg rrreans r the S lemma] secondand third relay means to operate, thereby conon h Solenordm the aservrrie veh'cre; necting said batteries in series with said outputcables. a rhrrd relay means havmg a coll r first and scrim-rd 4. Abattery booster circuit in accordance with claim 1 P of ni p Contacts, dC01 and the pair of wherein said control means includes in addition:contacts on said second relay means being connected in a a normally openswitch. series between ground and the positive terminal on said Y n n nb. a first relay means having a coil and a pair of normally F battery r53rd firsr Parr or contacts on S'frrd open contacts, said coil and saidswitch being connected thrrrrelay mrfans bemg arranged to connect thenegarrve in series between the output of said voltage sensing meansrermmal of 53rd first battery mearrs to gr and the ignition switch insaid road service vehicle; a fourth reray merms hrwmg a cor] and a r ofnormally c. a second relay means having a coil and a first and second 55open f Sard and second Parr r r pair of normally open contacts, saidcoil and the pair of Sard rhrrd relay means, P crmnected Serles normallyopen contacts on said first relay means being between ground and theposrtrve terminal on said second connected in series between ground andthe positive terbattery f t the P of contacts n said fourth relay minalon said second battery means, the first pair of normean? bemg arrangedto corrnect the posrtrve rermmals mally open contacts on said secondrelay means being aron said first and tterres together; and ranged toconnect the positive terminals of said firs't and means f' operatrvlycrmnecrmg r secorrd battery to Second batteries together. the startingsystem in said road servrce vehicle, whereby u a I a d a third relaymeans having a coil and a pair of normally said batteries Will beconnected in parallel to the road seropen contacts, said coil and thesecond pair of contacts vrce vehrcre s srarrmg System on said secondrelay means being connected in series

1. A battery booster circuit for use with a road service vehiclecomprising, in combination: a. a first battery means having positive andnegative terminals; b. a second battery means having positive andnegative terminals, the negative terminal on said second battery meansbeing connected to ground; c. first and second output cables, said firstoutput cable being connected to ground; d. current amplifying voltagesensing means having inputs operatively connected to said second outputcable and also to said first battery means, the output of said voltagesensing means being arranged to indicate whether said first batterymeans and said second output cable having been properly connected; ande. control means operatively connected to the output of said voltagesensing means, said control means being arranged to connect said firstand second batteries in series and parallel combinations to said outputcables, said control means also being arranged to connect said first andsecond batteries in parallel to the road service vehicle''s starting andcharging systems when said batteries are not connected to said outputcables.
 2. A battery booster circuit in accordance with claim 1 whereinsaid voltage sensing means comprises: a. a current amplifying meansconnected to be driven by current from the road service vehicle ignitionswitch or an accessory circuit operable with the engine of the roadservice vehicle; b. diode means connected to the output cable such thatimproper connection of the output cable to the emergency vehicle willprevent the operation of the amplifier and thus the meanS of operation;and c. diode means connected to the first battery means such thatimproper installation of said first battery will defer the drive currentfrom the amplifier such as to prevent the paralleling of said first andsecond battery means for either charging or starting.
 3. A batterybooster circuit in accordance with claim 1 wherein said control meansincludes, in addition: a. a normally open switch; b. a first relay meanshaving a coil and a pair of normally open contacts, said coil and saidswitch being connected in series between the output of said voltagesensing means and the ignition switch in said road service vehicle; c. asecond relay means having a coil and a pair of normally open contacts,said coil and the pair of normally open contacts on said first relaymeans being connected in series between ground and the positive terminalon said second battery means, the pair of normally open contacts on saidsecond relay means being arranged to connect the positive terminal ofsaid second battery means to the negative terminal of said first batterymeans; and d. a third relay means having a coil and a pair of normallyopen contact, said coil and the pair of normally open contacts on saidfirst relay means being connected in series between ground and thepositive terminal on said second battery means, the pair of normallyopen contacts on said third relay means being arranged to connect thepositive terminal of said first relay means to said second output cable,wherein said first relay means will operate when said switch is closed,said first relay mean causing said second and third relay means tooperate, thereby connecting said batteries in series with said outputcables.
 4. A battery booster circuit in accordance with claim 1 whereinsaid control means includes, in addition: a. a normally open switch; b.a first relay means having a coil and a pair of normally open contacts,said coil and said switch being connected in series between the outputof said voltage sensing means and the ignition switch in said roadservice vehicle; c. a second relay means having a coil and a first andsecond pair of normally open contacts, said coil and the pair ofnormally open contacts on said first relay means being connected inseries between ground and the positive terminal on said second batterymeans, the first pair of normally open contacts on said second relaymeans being arranged to connect the positive terminals of said first andsecond batteries together; d. a third relay means having a coil and apair of normally open contacts, said coil and the second pair ofcontacts on said second relay means being connected in series betweenground and the positive terminal on said second battery means, the pairof contacts on said third relay means being arranged to connect thenegative terminal on said first battery means to ground; and e. a fourthrelay means having a coil and a pair of normally open contacts, saidcoil and the pair of contacts on said first relay means being connectedin series between ground and the positive terminal on said secondbattery, the pair of contacts on said fourth relay means being arrangedto connect the positive terminal on said first battery to said secondoutput cable, whereby said batteries are connected in parallel with saidoutput cables.
 5. A battery booster circuit in accordance with claim 1wherein said control means includes, in addition: a. a first relay meanshaving a coil and a pair of normally closed contacts, said first relaymeans being activated while said battery booster circuit is being usedto service a disabled vehicle; b. a second relay means having a coil anda first and second pair of normally open contacts, said coil and thepair of normally closed contacts on said first relay means beingconnected in series between the output of said voltage sensing means andthe ignition switch in said road service vehicle, the first pair ofcontacts on said second relAy means being arranged to connect thenegative terminal on said first battery means to ground, the second pairof contacts on said second relay means being arranged to connect thepositive terminals on said first and second batteries together; and c.means for operatively connecting said second battery means to thecharging system in said road service vehicle, whereby said batterieswill be connected in parallel to the road service vehicle''s chargingsystem when said battery booster circuit is not being used to service adisabled vehicle.
 6. A battery booster circuit in accordance with claim1 wherein said control means includes, in addition: a. a first relaymeans having a coil and a pair of normally closed contacts, said firstrelay means being activated while said battery booster circuit is beingused to service a disabled vehicle; b. a second relay means having acoil and a pair of contacts, said coil and the pair of normally closedcontacts on said first relay means being connected in series between theoutput of said voltage sensing means and the ''''S'''' terminal on thesolenoid in the road service vehicle; c. a third relay means having acoil and a first and second pair of normally open contacts, said coiland the pair of contacts on said second relay means being connected inseries between ground and the positive terminal on said second batterymeans, said first pair of contacts on said third relay means beingarranged to connect the negative terminal of said first battery means toground; d. a fourth relay means having a coil and a pair of normallyopen contacts, said coil and the second pair of contacts on said thirdrelay means being connected in series between ground and the positiveterminal on said second battery means, the pair of contacts on saidfourth relay means being arranged to connect the positive terminals onsaid first and second batteries together; and e. means for operativelyconnecting said second battery to the starting system in said roadservice vehicle, whereby said batteries will be connected in parallel tothe road service vehicle''s starting system.